<template>
  <div id="app">
    <div class="box">
      <div class="left"></div>
      <div class="mid"></div>
      <div class="right"></div>
    </div>
  </div>
</template>

<script>
export default {

};
</script>

<style lang="less" scoped>
#app {
   .box {
      display: flex;
      width: 100%;
      height: 100vh;
      flex:1;
   }
   .left {
      flex: 1;
      background-color: hotpink;
   }
   .mid {
      flex: 1;
      background-color: gold;
   }
   .right {
      flex: 1;
      background-color: greenyellow;
   }
}
</style>